Seed yield and oil quality of perennial castor bean in a Mediterranean environment

ewline"> Castor (Ricinus communis L.) is an oilseed species, which in southern Italy iscultivated as annual during the spring-summer period under irrigation, but in mosttemperate areas such as those of eastern coast of Sicily, it could be grown as semiperennial with no irrigation, by the adoption of autumnal sowings. A fieldexperiment was conducted in southeastern Sicily with the aim of assessing plantsurviving, seed yield and oil quality of four castor genotypes originating fromdifferent geographical areas (two Sicilian, one Tunisian and one Brazilian). Thefavorable climatic conditions allowed the plant to survive during the fall-winterperiod. Seed yield reached 3.45 t ha-1 on average of the two years and seed oilcontent ranged from 45% (Tunisian cultivar) to 48% (‘Local RG 2’ Siciliangenotype). Oil yield reflected the variation in seed yield. Genetic diversity for fattyacid composition and saponification number, iodine value and cetane number wasevidenced. When ricinoleic acid is not taken into account, the oil of all genotypessatisfied the EU standards for biodiesel. The ricinoleic acid was the lowest (79%)in the Sicilian ‘Local RG 2’ and the highest (89%) in the Tunisian one, revealing agreater suitability of oil of the first genotype for biodiesel. In turn, the oil ofTunisian genotype could be exploited in other bio-based industrial sectors. Thestudy also demonstrated that in the southeastern coast of Sicily autumnal sowingsmight be advantageous for castor grown as semi-perennial crop, mainly since theyallow saving irrigation water.